Vector control offers a number of benefits including speed control over a wide range. For applications where high degree of accuracy in speed control is not required simple methods based on steady state equivalent circuit have been employed. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. Motor control centers mcc coupled with the asd using realtime monitors to trace motordrive system performance.
Induction machines guru nanak dev engineering college, ludhiana. In synchronous ac motors, the rotor turns at exactly the same speed as the rotating magnetic field. The ac electric motor used in a vfd system is usually a threephase induction motor. Ac motor, main drive controller assembly, and drive operator interface 210211 ac motor.
Before discussing about the induction motor drives we have to understand and know about induction motors. This book is devoted to various aspects of control of induction motors. Induction motor drives for variable speed applications, the dc motor drives are used in the past. Synchronous motor characteristics cylindrical and salient pole. Before discussing, induction motor drives its important to understand and know about induction motors. The control principles of various dc and ac motors using solid. Threephase induction motor, cage and wound slipring rotor, synchronous and rotor speed, slip, induced voltages in stator winding and rotor bar. The induction motor is made up of the stator, or stationary windings, and the rotor. Speed control of induction motor part 1 video lecture by prof. The stator is composed of laminations of highgrade sheet steel. Induction motor drives starting braking speed control of. This book is an early treatment of ac induction and permanent magnet synchronous motors.
The electric energy generated purchased by consumers for different needs. The reason of describing induction motors as constant speed is because normally these motors. Application notes vibration diagnostics for industrial electric motor drives the induction motor is the most widely employed industrial electricdrive. Nptel provides elearning through online web and video courses various streams. This paper presents design and analysis of a three phase induction motor drive using igbt. Induction motor and different speed control methods page no 3. Drives general 4 motor operation with converter supply 6 motor. Another way to drive a splitphase motor or a shadedpole motor uses a voltage doubler circuit with an hbridge inverter, as shown in figure 6. The basic idea of an electric motor is to generate two magnetic fields. Sms with a 4pole rotor operated at 50hz rotate in synchronism with the supply at exactly 1500rpm.
Linear induction motors are quite an engineering marvel, to convert a general motor for a special purpose with more or less similar working principle, thus enhancing its. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. Chapter 3 phase induction motor drives, ppt, electrical machines, semester, engineering electrical engineering ee notes edurev notes for electrical engineering ee is made by best teachers who have written some of the best books of electrical engineering ee. The alternating current ac induction motor is one of the most rugged and most widely used machines in industry. All we need to do is to keep daxis stator current constant. It is available from fractional horsepower ratings to megawatt levels. Speed control of induction motor part 1 video lecture. There are two major components of an ac induction motor. The induction motor, which is the most widely used motor type in the industry, has been favored because of its good selfstarting capability, simple and rugged structure, low cost and reliability, etc. Matlab simulation for speed control of three phase. Now these efficient motors are used in those applications where we aim at energy saving. Analysis of induction motor from nonsinusoidal voltage supply. These drives are also particularly suited to applications that must operate at very high speeds with a high level of field weakening, for example spindle motors.
The rotor will constantly be turning to align its magnetic field with that of the stator field. Umanand, principal research scientist, power electronics group, cedt, iisc bangalore for more detail. The 3phase set of currents, each of equal magnitude and with a phase. So, in that situation the two motors will not be running at the same speed. Fall 2005 ee595s electric drive systems 36 the plan continued achieving 14. Along with variable frequency ac inverters, induction motors. A method for parameters estimation in induction motor drives vasile horga 1 alexandru onea 2 mircea diaconescu1 1 department of electric drives 2 department of automatic control and industrial informatics gh. Nptel syllabus industrial drives power electronics video course 1.
The reason for describing induction motors as constant speed is because normally these motors. Vector control, also called fieldoriented control foc, is a variablefrequency drive vfd control method in which the stator currents of a threephase ac electric motor are identified as two orthogonal components that can be visualized with a vector. Lecture series on industrial automation and control by prof. Vectorcontrolled induction motor drives the previous control strategies good steadystate but poor dynamic response oscillation resulted from the air gap flux vector control fieldoriented control is related to the phasor control of the rotor flux. Synchronous motor drives, 3 volts per hertz and vector controlled induction. Most of the motors are uncontrolled, but the share of adjustable speed induction motor drives fed from power electronic converters is steadily increasing, phasing out dc drives. Control of induction motor through stator voltage variable voltage characteristicscontrol of induction motor by ac voltage controllers waveforms speed torque characteristics. The rotating stator magnetic field induces currents in the short circuited rotor. Nptel electrical engineering advanced electric drives. A sourcebook for industry by the piping and support structure.
Please find the full notes on electrical machines and drives. Induction machines guru nanak dev engineering college. In very simple words induction motors can be described as a threephase, selfstarting constant speed ac motors. This induces an electric field in a coil or squirrel cage to drive a. Right from its inception its ease of manufacture and its robustness have made it a very strong candidate for. A 3phase induction motor uses current delivered in three phases in a sequence into the coils of a stator to create a rotating magnetic field.
The previous control strategies good steadystate but poor. The book covers the following topics three phase circuits and power magnetics transformers concept of electrical machiners dc motors three phase windings induction. One well known approach is the utilization of synchronous motors sm. The reason for describing induction motors as constant speed is because normally these motors have a constant speed depending on the frequency of the supply and the number of. Induction motor drives electric vehicle machines and. An984, an introduction to ac induction motor control using. So, we can save this energy by using efficient induction motor in which. Power semiconductor drives pdf notes psd pdf notes. Motor and drive system basics 4 improving motor and drive system performance. Speed control of an induction motor requires position feedback information from an encoder, or a. An induction motor has two magnetically coupled circuits. This is similar to a transformer, whose secondary is rotating and shortcircuited.
Dec 17, 2019 in this method of speed control of three phase induction motor, the two threephase induction motors are connected on a common shaft and hence called cascaded motor. Induction motors are the most important workhorses in industry. The vector control of induction machine or induction motors especially are controls similar to that of a separately excited fully compensated dc machine. Ac induction motors how ac motors work explain that stuff. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses. Vector control of induction motor drives springerlink. Frequency control of induction motor fed from vsi and csi. Identifying the vibration problems that can occur in induction motor drives have an added complexity due to the rotating magneticfields in the machine. It consists of an electric motor motors, a transfer mechanism, an electrical energy converter, and a control system. Advent of advanced power electronic converters and powerful digital signal processors, however, has made possible the development of high performance, adjustable speed ac motor drives. T s t 2 3 2 3 sa b sc e i a i b in principle thedtc method selects one of the six nonzero and.
It is assumed that the students have prior exposure to electrical machines and power electronics. They are mostly used as constantspeed drives when fed from a voltage source of fixed frequency. Chapter 3 phase induction motor drives, ppt, electrical. Unit iv induction motor drives 3 by controlling the firing angle of the thyristors connected in each phase, the rms value of stator voltage can be varied. Basic electrical technology nptel online videos, courses iit video lectures. In the first course, mainly the dc motor control both steady state and dynamic, and steady state torque and speed control of ac motors are emphasized. List and describe the more commonly used equipment in an electric substation. You should also make a dc measurement of stator winding linetoline resistance using a dmm. But this motor has several disadvantages like the presence of commutator and brushes due to which frequent maintenance is required. Lecture 6 three phase induction motors cairo university. Record all nameplate information for the induction motor. In an induction motor, the electric current in the rotor needed to produce torque is obtained via electromagnetic induction from the rotating magnetic field of the stator winding. It supplies an induction motor ich has a full load speed of 144wh 0 rpm. Types, construction and principle of operation, 3 phase induction motor, general phasor diagram, equivalent circuit, power and torque relations, condition for maximum torque.
A successful salesman for general electrics motor division once remarked to one of your instructors that, when asked by a customer how a motor. One motor is the called the main motor, and another motor is called the auxiliary motor. In this circuit, the switching devices will see a higher dc bus voltage. Applied intelligent control of induction motor drives. A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. Pdf induction motors are the most frequently used machines in different electrical drives. Operation of induction motor with unbalanced source voltages. A method for parameters estimation in induction motor drives. A tutorial in ac induction and permanent magnet synchronous motors, vector control with digital signal processors, fred flett, analog devices, 1994. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. Speed control of synchronous motor pdf dc motor drive since ac motors were not capable of smoothly varying speed.
What is common to all the members of this family is that the basic physical process involved in. It is logical that the least expensive, lowest maintenance type motor should be used most often. This chapter discusses various induction motor drives. Induction motor drives version 2 ee iit, kharagpur 2 instructional objectives after learning the lesson students should be able to understand a.
This problem is overcome by the variable speed induction motor drive. Among the various categories of mpc, fs mpc with short prediction horizon. Mostafa elshahed objectives learn a brief history of the electrical power systems construction. Nptel syllabus industrial drives power electronics. Right from its inception its ease of manufacture and its robustness have made it a very strong candidate for electromechanical energy conversion. Some types of singlephase motors or synchronous motors.
Synchronous motors controlled by variablespeed drives are. Suppose let us take the first situation separately excited dc motor, and we are supplying. The efficiency of induction motor drives operating under variable conditions can be improved by. Basic electrical technology nptel online videos, courses. What is common to all the members of this family is that the basic physical process involved in their operation is the conversion of electromagnetic energy to mechanical energy, and vice versa. Speed control of three phase induction motor electrical4u. Pdf model predictive control of induction motor drives. Higher starting torques at low speeds up to 150% running torque up to 500 hp, in voltage source drives. A variablefrequency drive is a device used in a drive system consisting of the following three main subsystems. They are generally more expensive than induction motor dri ves,but the advantages is that the efficiency is higher,which is tends to lower the life cycle cost. One component defines the magnetic flux of the motor, the other the torque.
Induction machines 1 introduction the induction machine was invented by nikola tesla in 1888. Singlephase induction motor threephase induction motor singlephase induction motor there are probably more singlephase ac induction motors in use today than the total of all the other types put together. Application notes vibration diagnostics for industrial. Differentiate between the various types of generating electric power stations. Vectorcontrolled induction motor drives the previous control strategies good steadystate but poor dynamic response oscillation resulted from the air gap flux vector control fieldoriented control is. Find the percentage slip and number of poles of the induction motor. Such an induction motor with integrated brake is shown on figure 1. Apr 04, 2008 lecture series on power electronics by prof. Advanced electric drives video course course outline the first course on electric drives usually introduces the concept of control of electric motors for various types of mechanical loads. In very simple words induction motors can be described as a three phase, self starting constant speed ac motors. Fall 2005 ee595s electric drive systems 42 direct field oriented control b iacdeisa. The motor is mounted in a test rig that allows one to control the torque applied to the motor.
As a result of this, the motor torque and the speed of the motor. Be careful it can hurt to tangle with a threephase motor. In the first course, mainly the dc motor control both steady state and dynamic, and steady state torque and speed control of ac motors. Analysis of induction motor drive with direct torque control scheme using space vector modulation a thesis submitted in partial fulfillment of the requirements for the degree of master of technology in electrical engineering power electronics and drives by vudatha vinod kumar roll no. Induction motors in practice what controls the speed of an ac motor. Lecture series on basic electrical technology by prof. Essentially, the control problem is reformulated to resemble the control of a dc motor. They are generally more expensive than induction motor dri ves. Induction motor drives with closedloop control are used in similar applications to d. Advanced electric drives video course electrical engineering nptel.
1467 662 160 721 1347 372 388 835 1089 1064 1153 811 1569 75 1048 500 415 1574 1088 651 1216 1073 1018 961 425 892 294 98 1162 741 1586 1231 964 203 1579 360 1010 1454 1033 113 658 189 190 1171 559 561 948